Field
Aspects of the present invention generally relate to an image forming apparatus, a method for controlling an image forming apparatus, and a storage medium.
Description of the Related Art
An image forming apparatus such as a printer receives a print job from an external apparatus such as a personal computer (PC) and compares sheet feeding setting information (sheet settings and cassette specifying) described in the received data with sheet setting information set for cassettes (sheet cassettes including a manual-feeding tray are referred to as “cassettes”) of the image forming apparatus. Then, the image forming apparatus selects a cassette in which an appropriate sheet is set, and executes printing. The sheet setting information of each cassette includes a sheet size and a sheet type (plain paper or thick paper), and according to the sheet size and the sheet type, the image forming apparatus adjusts a sheet conveyance speed and a toner fixing temperature in a printing unit and executes printing. The sheet type indicates the type of a sheet and is defined by the basis weight (weight per unit area) and the surface property of the sheet. For example, sheets different in thickness are classified into plain paper, thin paper, and thick paper, based on their basis weights. Further, the plain paper may be subdivided into plain paper 1, plain paper 2, and plain paper 3. For example, sheets different in material are classified into overhead projector (OHP) film and coated paper, based on their surface properties.
There are a case where a user manually sets the sheet setting information of each cassette, and a case where the image forming apparatus detects a set sheet using a sensor and automatically sets the sheet setting information of each cassette. Conventionally, there has been an image forming apparatus that automatically detects a sheet size using a sensor. In recent years, an image forming apparatus capable of automatically detecting a sheet type (plain paper or thick paper) using a sensor has also appeared. This sheet type detection eliminates the need for the user to manually set a sheet type when a sheet is set in a cassette. This improves the convenience of the image forming apparatus. The sheet type detection, however, is performed not in the state where a sheet is set in a cassette, but in the state where the sheet is conveyed from the cassette to a sheet discharge tray. Thus, the image forming apparatus performs sheet type detection in a print job to be executed after the user sets the sheet in the cassette. Then, the image forming apparatus registers the detection result as sheet setting information of the cassette. Japanese Patent Application Laid-Open No. 2014-133656 discusses a technique for performing sheet type detection and storing the detection result as sheet setting information of a cassette.
If, however, a sheet type is specified in sheet feeding setting information of a print job, sheet type detection cannot be performed. Thus, a cassette cannot be selected, and the job stops due to the absence of a sheet. This is because, as described above, sheet type detection is performed not in the state where a sheet is set in a cassette, but in the state where the sheet is conveyed from the cassette to a sheet discharge tray. As a result, for a job in which a sheet type is specified (for example, plain paper), it is not allowed to perform printing in the state where a sheet type is not identified (for example, actually, thick paper is set). If the job stops due to the absence of a sheet, not only the job cannot be executed, but also the succeeding jobs are kept waiting and stop. Even if the succeeding jobs include a job that can be executed, the job stops.